Measuring apparatus employing variable frequency transducer

ABSTRACT

Torsion, horsepower, and specific fuel rate measuring apparatus includes vibrating wire transducers secured about the periphery of a coupling shaft. Digital apparatus is provided to generate a pulse train having a frequency proportional to the square of the vibrating wire frequency to develop torsion information. The digital torsion wave train is then employed together with a pulse sequence characterized by a rate dependent upon the rotational shaft speed to generate an asynchronous pulse train having a frequency proportional to the horsepower coupled by the shaft. A fuel flow transducer generates pulse information which is combined with the horsepower signal to provide a figure of merit characterizing a composite power plan, viz., specific fuel rate defined by the ratio of the useful horsepower output of the plant to the rate at which fuel is consumed by the plant to develop that power.

United States Patent Judlowe [45] Aug. 15, 1972 [54] MEASURING APPARATUSEMPLOYING VARIABLE FREQUENCY [5 7] ABSTRACT TRANSDUCER Torsion,horsepower, and specific fuel rate measuring [72] Inventor: Stephen B.Judlowe, 47 Sagamore apparatus includes vibrating wire transducerssecured Dr., Murray Hill, NJ. 07971 about the periphery of a couplingshaft. Digital ap- [22] Filed. Oct 8 1970 paratus is provided togenerate a pulse train having a frequency proportional to the square ofthe vibrating PP 79,020 wire frequency to develop torsion information.The digital torsion wave train is then employed together 52 us. c1..73/136 A, 73/114, 73/1173 with a 1W1Se Sequence characterized by arate depen- [Sl] Int. Cl. ..G0ll 3/10 dent upon the rotational shaftspeed to generate [58] Field ofSearch..73/l36 A, 117.3, 116,517 AV,asynchronous Pulse tram having a frequency P p 7 3 1 t1onal to thehorsepower coupled! by the shaft. A fuel flow transducer generates pulseinformation [56] References and which is combined with the horsepowersignal to pro- UNITED STATES PATENTS vide a figure of meritcharacterizing a composite power plan, viz., specific fuel rate definedby the ratio 3,290,930 12/1966 Drlnkwatel' ..73/136 A f h f horsepoweroutput of the plant to the 3,545,265 12/ 1970 Mcllra th ..73/136 A rateat Which fuel i consumed by the plant to develop 3,573,448 4/1971Valentine ..235/ 150.52 that power Primary Examiner-Jerry W. Myracle 14Claims, 4 Drawing Figures COMMUNICATION a LINK l E OSCILLATOR I 24 26 F2F1 1 F2 FREQUENCY FREQUENCY MULTIPLIER MULTIPLIER 45 OCT. 9311 1 1L. 2 kF (23:04 51"" cc'r so TIMING ccT. 51

RPM ms o- FREQUENCY FREQUENCY Mk ANALOG MULTIPLIER MULTIPLIER 1 LCONVERTER CIRCUIT \54 CIRCUIT I 55 Mi 1% FREQUENCY-T0 FREQUENCY-TO- 5BVOLTAGE VOLTAGE A50 CONVERTER CONVERTER 73 I FUEL HP now (ANALOG) 72\FRisouEcv-Tm I METER DIFFERENCE 74 com/gag? I AMPLIFIER m'reRAToR 92(VCO-DIVIDER PATENTEIIIUBI 5 m2 3.683.684

SHEET 1 III 3 ROTATION SPEED SIGNAL CONDITIONING i APPARATUS 50 P F/G.

FROM FROM CCT. 45 CCT 46 KI fi l I IQ FREQUENCY DIFFERENTIATOR 8ONETWORK 2 2 K F -F I" RPM PULSES I 2 I I FRoM CCT.5O

FREQUENCY MULTIPLIER 8| CIRCUIT PECIFIC s PULSE FUEL RATE HP r I I I 82I 84 I 73 coMPARA- I I TOR FREQUENCY I FUEL I MULTIPLIER I FLOW 4NETWORK METER I7 90 DIVIDER PATENTEDIIIIQ I 5 I972 3 5 584 SHEEI a or 526 so 2 F1612 OSCILLATOR II COMMUNICATION LINK l8 as OSCILLATOR 24 j 16F2 Fl n FVFZ FREQUENCY FREQUENCY MULTIPLIER MULTIPLIER KI FL. RPM KIFROM) ccrso F3 TIMING CCT. 5I

RPM D|G|TA| -TQ- FREQUENCY FREQUENCY m ANALOG i MULTIPLIER MULTIPLIERLOQLCONVERTER CIRCUIT CIRCUIT 2 K2KI+IF3 KZK'F 3 FREQUENCY-ToFREQUENCY-TO- VOLTAGE VOLTAGE 58 CONVERTER CONVERTER 73 FUEL HP FLOWNIETER (ANALOG) 72\ FREQUECY-TO- I I 74 coIIiI ifiR DIFFERENCE DMDERAMPLIFIER T 62 SPECIFIC INTEGRATOR COUNTER FUEL 92 (VCO-DIVIDER) 94 RATEPATENTEDAus 15 1912 SHEET 3 OF 3 LOGIC OUTPUT S ROBE FROM TIMING NETWORK5| DELAY CLEAR I FIG. 3

MEASURING APPARATUS EMPLOYING VARIABLE FREQUENCY TRANSDUCER DISCLOSUREOF INVENTION This invention relates to electronic instrumentation and,more specifically, to improved apparatus for determining the torque,horsepower and specific fuel rate associated with a coupling shaft andits concomitant driving plant.

Rotating shafts are very commonly employed as a mechanical coupling toconvey power from a driving energy source to a driven element, e.g.,from a ships steam turbine or diesel engine to a propeller. In someapplications, as for modern tanker vessels, the coupling shaft may behundreds of feet long and several feet in diameter to couple the greatpropulsion energy required.

It is desirable to measure the torque and horsepower transmitted by ashaft for several reasons, as to provide a figure of meritcharacterizing the operational status of the driving plant; the statusof the power transmission structure which typically includesshaft-supporting bearings; and also to provide information regarding thedriven element.

For relatively small shafts in the inch or several inch diametercategory, intermediate load sensing coupling links may be directlyinserted in the shaft train to measure the coupling torque which, whenmultiplied by the shaft rate of rotation provides horsepowerinformation. However, for the huge shaft applications such as discussedabove, it is obviously impractical to interrupt the shaft for horsepowermetering purposes. Accordingly, for the large shaft applications,torsion sensing strain gauges or other transducer forms have beenmounted on the shaft and connected to, horsepower determining apparatuseither by slip rings, or some form of telemetering link. However, suchprior horsepower metering apparatus for large shaft applications hasbeen less than completely satisfactory, such equipment typicallyemploying complex, burdensome, expensive and/or relatively inaccurateand drift-prone analog apparatus to effect the requisite measurement andderived parameter computation.

It is therefore an object of the present invention to provide improvedtorsion, horsepower and specific fuel rate metering apparatus. I

More specifically, an object of the present invention is the provisionof the aforesaid apparatus which may be readily constructed, and whichprovides accurate, repeatable and stable output data.

The above and other objects of the present invention are realized inspecific, illustrative horsepower metering apparatus wherein twovibrating wire transducers are secured circumferentially about a powercoupling shaft. The transducers when excited exhibit characteristicoutput oscillation frequencies which vary as the square root of theshaft torsion such that the difference between the square of thetransducer frequencies provides a direct measure of shaft torsioncorrected for temperature and other environmental effects. Thetransducer output frequencies are coupled from the shaft to a stationaryreceiver, as is the shaft rotational speed, via a plurality of signalcoupling channels.

The receiver employs digital circuitry for developing two asynchronousdigital pulse trains each having a frequency proportional to the squareof one of the transducer output frequencies. These two pulse trains are,in turn, operated upon together with the shaft revolution speed pulsesequence to form additional characteristic pulsed waves each providing apulse encoding of shaft horsepower. The difference is then taken betweenthese latter signals to provide horsepower output information.

In accordance with other aspects of my invention, the horsepower signalmay be divided by a measure of the rate of fuel consumption, or fuelflow. In addition, an integration of horsepower may be effected toprovide horsepower hour information.

The above and other features, objects and advantages of the presentinvention are realized in a specific illustrative embodiment thereof,presented hereinbelow in conjunction with the accompanying drawing inwhich:

FIG. 1 schematically depicts transducer and shaft revolution ratesignalling apparatus included on a shaft;

FIG. 2 is a block diagram depicting a data processing system embodyingthe principles of the present invention;

FIG. 3 illustrates frequency multiplying circuitry repeatedly employedin the arrangement of FIG. 2, and

FIG. 4 is a block diagram depicting alternate specific fuel ratedetermining apparatus.

Referring now to FIG. 1, there is shown a section of a power couplingdrive shaft 5 employed to convey power from a drive source to a drivenelement. To determine the torque, or torsion in the shaft at any giventime, which directly comprises useful information and as required todetermine the several derived quantities such as horsepower and specificfuel rate, two spaced collars l0 and 16 are rigidly secured to the shaft5, one collar, e.g., the collar 10 having two spaced projections l2 and14 thereon, and the other collar 16 having an intermediate projection18.

Two taunt transducer wires 22 and 24 are respectively connected betweenthe projections 12 and 18, and 18 and 14 via standoff elements whichelectrically insulate the wires from the shaft 5. As discussed belowregarding FIG. 2, the wires 22 and 24 are employed to provide feedbackcouplings for two independent oscillators which excite the transducers,the oscillators thereby providing an electrical output corresponding tothe natural resonant frequencies of the wires 22 and 24.

The tension in the wires 22 and 24 is initially adjusted to besubstantially equal when no power is applied to the shaft 5 such thatthe wires 22 and 24 have substantially like resonant frequencies. Whenpower is applied to the shaft 5 in a direction 20 shown in FIG. 1, acorresponding torque is established in the shaft in that direction.According y the tension (and resonant frequency) in the wire 24increases, while that in the wire 22 decreases. Conversely, when theshaft 5 couples power in the driven direction 22, the internal torsionin the shaft increases the resonant frequency of the wire 22, anddecreases that of the wire 24.

The natural frequency of a taunt vibrated wire varies as the square rootof the applied torsion. Thus, the differences between the squares of theresonant wire frequencies provides a direct measure of the torsion inthe shaft. The difference between the square of the frequency in eitherwire 22 or 24 and the square of the frequency of that same wire when nopower is applied to the shaft 5 provides complete torque information.However, the two wires are employed to reject common mode signal errors,for example, temperature variations which produce similar effects in thetwo wires 22 and 24. Further, the two wires essentially provide adoubling of the output frequency shift informatron.

To provide a measure of the shaft rotational speed, revolution ratesignaling apparatus is employed in the arrangement of FIG. 1, such asone or more magnets 26 secured to one of the shaft collars and astationary reed switch 28 which is activated each time each magnet 26rotates thereby. The shaft rotational speed, or RPM information issupplied to an RPM pulse conditioning circuit 50 which may comprise, forexample, any current sinking logic gate such as a single DTL or TFLgate, or such a gate followed by a one-shot pulse timing network.

The system for making use of the vibrating wire information is shown inblock form in FIG. 2 and comprises two oscillators 34 and 36 forexciting the wires 22 and 24 for vibration at their natural frequencies.Examining the oscillator 34, also illustrative of the oscillator 36,there is employed first and second electromagnets 26-30 and 28-32. Oneof the electromagnets e.g., the winding 30 about the ferromagnetic core26, is employed to excite the wire by providing a wire actuatingalternating magnetic field at or about the center of the wire 22. Thevibrating wire, in turn, induces an alternating current signal potentialin the winding 32 as it cyclically approaches and moves away from theferromagnetic core 28 and winding 32. Configurations for the oscillator34 for vibrating the wire 22 are well known. For example, theoscillators 34 and 36 may be of the tickler feedback or other typewherein the winding 30 is connected in the collector circuit of adriving transistor stage, and the winding 32 included in the input orbase control circuit for the driver. The oscillators 34 and 36 willautomatically operate at the natural frequency of the associated wire 22or 24 since the wire can provide feedback signals only at that frequencyto the feedback winding 32 when pulsed by the winding 30.

The oscillator output frequencies f and f are coupled to frequencymultiplying circuits 45 and 46 via any two channel signal communicationlink 38, c.g., slip rings coupling signals from the rotating shaft 5 tothe stationary receiver, or by way of a telemetering link. Theoscillators 34 and 36 will nominally be mounted on the shaft for thetelemetering application, and may be included on the stationary receiverand connected as required to the windings 28 and 30 by additional trackswhere slip rings are employed.

Each frequency multiplying circuit 45 and 46 provides an asynchronousoutput pulse train of an average frequency proportional by the sameproportionality factor to the square of the applied input frequency. Thestructure of the frequency multiplying circuits 45 and 46 is shown inFIG. 3 and is discussed below. It is ob served here, however, that thecircuitry 45-46 is digital in nature such that repeatable, accurate dataprocessing, free of drift, is effected by these circuits and by theremaining functional elements employed in the FIG. 2 arrangement.

The output pulse train from the frequency multiplying circuit 45(asynchronous pulses at a rate K, f and the pulse wave from the RPMcircuit 50 which occur at the shaft revolution rate or an integralmultiple thereof f are supplied to a frequency multiplying circuit 54which generates an asynchronous output pulse train of average frequencyK K F f Correspondingly, the output of the multiplying circuit 46 reactswith the RPM pulse train 'to form an asynchronous output pulse train offrequency k, k, ff )3. The output frequency of each pulsed output fromthe circuits 54 and 56 embodies complete information to identify shafthorsepower, as does the difference between these frequencies. Either oneof these pulse trains may be converted to analog form to provide ananalog horsepower indication; the output pulses can be repeatedlycounted over a fixed time interval to yield horsepower in digital form;or either technique can be used for each of the data processing channelsand the difference between the respective outputs taken to provide theoutput information. In this latter regard, and as shown in the drawingby way of specific illustration, the output of each frequencymultiplying circuit 54-56 is converted to analog form byfrequency-to-voltage converters 58 and 60, and the difference betweenthe outputs of the converter 58 and 60 taken by a difference amplifier62 to develop an analog horsepower signal. Varying structures for thefrequency-to-voltage converters 58 and 60 are well known and maycomprise, for example, an input pulse timing and regenerating one-shotmultivibrator followed by an integrator with a time constant which islong with respect to the input pulse repetition rate; a low pass filter;or as an intermediate signal more fully discussed below, by employingthe counter and latch of the FIG. 3 digital multiplier together with adigital-toanalog converter connected to the several register digitaloutputs. The analog replica of the shaft speed RPM signal may be derivedfrom intermediate digital voltages in the multiplier circuit 54 or 56 bya digitalto-analog converter 52, as will be more clear from thediscussion below regarding the multiplier of FIG. 3.

A pulse rate multiplying circuit suitable for use for the functionalcircuits 45, 46, 54, and 56 of FIG. 2 is shown in FIG. 3, and comprisestwo input terminalsand 91 for receiving either one or two input pulsetrains depending upon the circuit application. For the squaring mode ofoperation desired for the circuits 45 and 46, only a first pulse trainof frequency f is applied to the terminal 91 and therefrom to the inputof an n-stage binary counter 60. The pulse trains f are also connectedto the input of an n-stage binary counter 68 which advantageouslyincludes a number of stages identical to that of the counter 60.

The input pulse train at the multiplier terminal 91 may be directlyconnected to the input of the counter 68. However, to average thehorsepower signal over some appreciable time period, to eliminatespurious noise signals, or to limit measuring band width to that of along interval sampling recorder, c.g., over several seconds or minutes,the input frequency f,, is advantageously scaled down in frequencybefore being supplied an an input to the counter 68, as from one of thedivider stages in the counter network 60 which is otherwise required inany event. When connected in plurality of counter output terminals61,-61, are sup plied to a corresponding number of differentiatornetworks 64 which may be formed of a series capacitor and shuntresistor. Accordingly, each time any of the output terminals undergoes atransition from its low to its high voltage state, a positive pulse. isgenerated across the corresponding differentiator resistor.

Listed below is the digital count pattern for'an assumed four statecounter network 60, it being clear that any number of stages may beemployed.

Table l Output Terminals Count State 61, 61, 61, 61,

3 0 0 1 1 4 O l 0 0 5 0 l 0 l 6 O t l 1 0 7 0 'l l l 8 l 0 0 0 9 l 0 0 l10 l 0 l 0 11 -l 0 l l 12 l l 0 0 13 l l 0 l 14 1 l l 0 15 l l 1 l 16 O0 0 0 With reference to Table 1, it is observed that the voltage at oneand only one output terminal 6l,--61, changes from the binary zero (low)to the one (high) state responsive to each applied input pulse suppliedto the terminal 91, except for the last state when the counter is resetfrom full capacity to the all zero state whereupon no such transitionoccurs. Moreover, .it is observed that eight such transitions occur atthe output 61, of'the last significant counter stage; four transitionsoccur at the second least significant terminal 61 two such transitionsare present at the second most significant counter terminal 6l,,, andonly one transition for the most significant counter stage terminal 61,for each full counter complement of sixteen input pulses.

This 842--l pattern follows a binary weighted network, and supplied tothe latch to periodically transfer the count state of the counter 68into the latch. A replica of the strobe pulse passes through a delay element 87 and periodically clears the counter 68 to its all zero stateshortly after the strobe signal. The interval between successive counterclearing pulses is made sufficiently short so that the counter cannotoverflow from input. pulse supplied during that time interval, i.e., sothat the counter 68 does not receive more than 2 pulses betweensuccessive clear signals for the highest frequency anticipated for theinput terminal 91. The latch is strobed shortly before the counter 68 iscleared. The latch thus stores the highest count state of the countercorresponding to the number of pulses which occur between successiveclear pulses. The digitalnumber present at the latch output terminals isthus directly proportional to the frequency of the pulses supplied tothecounter 68, the peak count state for the counter 68 increasing ordecreasing with like changes for the input wave.

The signals present at the output latch terminals 71,-71 and at theoutput nodes of the differentiators 64,-64 are connected to inputterminals of n coincidence gates in reverse order of significance, i.e.,61, and 71,, 61 and 71, 61, and 71,. That is, the most significant bit,at the latch terminal 71,, is connected to the coincidence gate 80, withthe output of difi'erentiator 64,, associated with the output 61, of theleast significant counter 60 stage and so forth, the least significantbit at latch terminal 71, going to a coincidence gate 80,, with the mostsignificant output of counter by way of the differentiator 64,. Theoutputs of the several coincidence logic gates 80 are connected througha disjunctive, OR logic gate to the multiplier output terminal 86.

As is apparent, boththe digital number present at the output latchterminals 71 and the rate at which pulses are produced by thedifferentiators 64 directly depend upon the input signal frequency f,.Further the frequency at which pulses occur at the multiplier output 86depend upon the product of these dependent quantities, thediflerentiators and counter determining the number of pulses producedper unit of time, and the latch controlling the number of pulses asproduced which are allowed to proceed through the coincidence gates 80to the output terminal 86. For example, if the'most significant outputbit at terminal 71, of the latch is a digital one, the gate 80, will befully enabled to switch each time the differentiator 64, provides anoutput pulse, or every other input pulse. The output pulses from theenabled gate 80,, as for all other gates 80, pass through thedisjunctive logic gate 85 to the multiplier output terminal 86. If thepulse rate is sufficiently small (less than one-half maximum) such thata low (binary zero) voltage is present at the terminal 71,, one-half ofall input pulses applied at the input terminal 91 to not give rise to apulse at terminal 86 since the gate 80, is inhibited. Similarly, abinary one or zero at the temiinal 71, will give rise to the presence orabsence of an output pulse for every fourth input pulse, and so forthdown to the least significant bit at latch output terminal 71, whichcooperates with the coincidence gate 80,, differentiator 64,, and mostsignificant counter 60 out put terminal 61, to control the presence orabsence of only a single pulse at the output terminal 86 during a fullseries of 2" input pulses. Some reflection will show that the outputpulse train at terminal 86 thus exhibits a frequency 1, which isproportional to the square of the input pulse wave frequency, i.e.,fl,=kf The constant of proportional k is given by k= l/mXt/2"X2" /2"Equation where m is the division factor effected by the counter network60, or the number one if the temiinal 91 is directly connected to theinput of the counter 68;

t is the time interval between successive clear pulses, and

n is the number of stages in the counters 60 and 68, l

and the latch 70.

To produce pulse train frequency multiplication between differentvariables as for the circuits 54 and 56, i.e., to operate the multiplierof FIG. 3 in a nonsquaring mode, the jumper 63 is deleted. One of thetwo multiplicand pulse trains, e.g., the output of the squaring circuit45 or 46, is then connected to one multiplier input 91 while the othermultiplicand variable, i.e., the RPM pulse train is connected to theremaining input terminal 90. The circuit operates in a manner discussedabove, except that the two factors having a product relationship bearingupon the frequency of the pulse wave at the multiplier output terminal86, viz., the digital state of the latch 70 and the rapidity at whichpulses are distributed in a binary weighted manner at the output of thedifferentiators 64, are controlled by independent input pulse trains offrequency f and f,,.

The pattern of digital signals present at the output latch terminals 71-71,, provide a direct measure of the information embodied by the inputfrequency of the wave supplied to the counter 68. Where, as for thecircuit 54 (or 56), this input frequency information comprises RPM data,the digital signals at the latch terminals 71 may be supplied to adigital-to-analog con verter (e.g., a ladder or binary-weighted resistornetwork) to provide an alalog RPM signal.

Another important figure of merit beyond horsepower for a propulsionsystem is specific fuel rate, which indicates the amount of useful powerdelivered by a power source (horsepower) vis-a-vis the amount of fuelbeing consumed to generate this power (fuel flow). Specific fuel rate isthus defined to comprise the ratio of these variables. To this end, afuel rate meter 70, e.g., of the positive displacement type whereinturbine vanes rotate a metering disc at a rate dependent upon the rateof fuel flow in a conduit, may be employed in the system of FIG. 2. Thefuel flow meter 70 provides a series of output pulses, often manifestedby repetitive contact closures, the rate of which comprises a directmeasure of fuel flow. In accordance with the embodiment of the inventionshown in FIG. 2, the fuel rate pulses are converted to analog form by afrequency-to-voltage converter 72, and specific fuel rate is computed inan analog divider 74 which determines the horsepower-fuel flow quotient.

Moreover, the total useful ships propulsion output (horsepower-hours)may be derived by integrating the analog horsepower analog signal. Thismay be approximated in digital form by driving a voltage controlledoscillator (with optional divider) 92 and horsepowerhour counter 94 withthe analog horsepower signal.

In accordance with other aspects of my invention and as shown in FIG. 4,horsepower, and specific fuel rate may be computed on a digital basistaking advantage of the pulse train nature of all requisite computationvariables. The pulse rates k, f, and kafg proportional to the square ofthe transducer frequencies (torque), as determined by the circuits 45and 46 of FIG. 2, are supplied as inputs to a frequency differencenetwork of any known type, e.g., a simple flip-flop having set and resetinput terminals respectively controlled by the input pulse trains, andwhose two output ports selectively partially enable coincidence logicdirectly supplied with the pulse input trains. The output from thefrequency difference network 80 is supplied to a frequency multiplyingcircuit 81 (as of the FIG. 3 type) together with the RPM pulse train.The circuit 81 performs a function comparable to the circuits 54, 56,58, 60 and 62 of FIG. 2, viz., generating output information descriptiveof horsepower, in this case an output pulse train having a frequencyproportional to horsepower, i.e., proportional to the torsion and RPMproduct.

The pulse horsepower and fuel rate wave trains arev supplied to adigital divider 90 which includes a feedback loop comprising a frequencycomparator 82, a voltage controlled oscillator 84, and a frequencymultiplying network 86 as of the FIG. 3 configuration. The feedback loopof the divider 90 operates to automatically maintain the frequencyoutput of the network 86 essentially at that of the horsepower inputpulse train supplied by the circuit 81. To this end, the comparator 82supplies a control voltage signal to the variable frequency oscillator84 which directly provides an analog measure of specific fuel rate. Inparticular, it is apparent that since the frequency multiplying network86 comprises the product of the fuel rate frequency and the controloutput of the variable frequency oscillator 84, and since the output ofthe network 86 is maintained at the horsepower frequency, that theoutput of the oscillator 84 represents in pulsed form the quotient ofthe horsepower frequency and fuel flow frequency as desired. Afortiorari, the control voltage input to the variable frequencyoscillator 85 provides an analog measure of this information.

The above apparatus thus operates in a reliable manner to computetorsion, horsepower, and specific fuel rate by digital pulse ratetechniques, without requiring transducer conversions to digitalcombinatorial or analog arithmetic" systems. The arrangement is subjectto ready assembly since repetitive use is made of a single frequencymultiplying network, and accurate data, limited as a practical matter bythat of the sensing transducers, obtains from the avoidance of signalconversions.

The above-described apparatus is merely illustrative of the principlesof the present invention. Numerous modifications and adaptations thereofwill be readily apparent to those skilled in the art without departingfrom the spirit and scope of the present invention.

What is claimed is:

1. In combination in apparatus for measuring physical parametersassociated with a stressed body having a vibrating wire transducermounted thereon for providing an output signal which varies in frequencywith the applied stress, means for providing an output pulse trainhaving a frequency proportional to the square of the transducerfrequency, said frequency square proportional means comprising a firstcounter having a plurality of stages, means connected to each of saidfirst counter stages for producing an output pulse responsive to apredetermined voltage transition for said counter, a plural stage secondcounter, means for supplying a measure of the transducer frequency toeach of said first and second counters, a plural stage data register,means for periodically gating the contents of said second counter intosaid data register, means for periodically resetting said second counterafter data is transferred from said second counter to said register, aplurality of coincidence logic gates each having inputs connected to adifferent one of said pulse generating means and to a different stage ofsaid register, said connections for the inputs to the coincidence gatesbeing of an inverse order of significance with respect to the stages ofsaid first counter and the stages of said register, and disjunctivelogic means for providing an output pulse responsive to an output signalfrom any of said coincidence gates, said disjunctive logic means therebyproviding a pulse rate of frequency proportional to the stress obtainingin the stressed body.

2. A combination as in claim 1 further comprising frequency-to-voltageconverting means connected to the output of said disjunctive logic meansfor producing an output analog signal.

3. A combination as in claim 1 wherein said counter stages each compriseactive, low impedance output driver means for the zero to one statetransition, and wherein said pulse producing means connected to each ofsaid first counter stages comprises a differentiator.

4. A combination as in claim 1 wherein the input of said second counteris connected to the output of one of the stages of said first counter,such that the transducer output information is averaged for an extendedperiod of time.

5. In combination in means for measuring parameters associated with arotating shaft, vibrating wire transducer means secured to said shaftfor generating an output signal characterized by a frequency whichvaries with the torsion present in the shaft, frequency squaring meansfor producing a pulse train having a frequency proportional to thesquare of said transducer output frequency, means for developing a pulsetrain proportional to the rate of rotation of the shaft, and frequencymultiplying means for producing an output pulse train having a frequencyproportional to the product of said revolution rate pulse trainfrequency and the frequency of the output pulses generated by saidfrequency squaring means.

6. A combination as in claim 5, further comprising frequency-to-voltageconverting means connected to the output of said frequency multiplyingmeans.

7. A combination as in claim 5 wherein said frequency multiplying meansincludes register means for storing one input frequency variable inparallel binary form, and further comprising digital-to-analog convertermeans connected to said register means of said frequency multiplyingcircuit.

8. A combination as in claim 5 wherein at least one of said frequencysquaring means and said frequency multiplying means comprises first andsecond counters each having a plurality of stages, plural pulsegenerating means each connected to a different stage of said firstcounter for generating an output pulse responsive to each zero to onelevel transition for the associated stage of said first counter, aplural stage latch having a plurality of inputs connected to said secondcounter, timing means for periodically transferring data from saidsecond counter to said latch and for resetting said latch, pluralcoincidence logic gates, each having first and second inputs connectedto said pulse generating means and to said latch stages in an inverseorder of significance, and disjunctive logic means including pluralinputs connected to the outputs of each of said coincidence gates.

9. A combination as in claim 5 further comprising additional transducermeans secured to the shaft and circurnferentially aligned with saidtransducer means for providing an output signal frequency which variesfrom a quiescent frequency in a direction opposite to said transducermeans, additional frequency squaring means for producing an output pulsetrain having a frequency proportional to the square of the outputfrequency of said additional transducer means, and means for providing ahorsepower signal comprising means for computing the product of saidshaft rate of revolution and the difference in frequencies of the outputpulse trains generated by said frequency squaring means and saidadditional frequency squaring means.

10. A combination as in claim 9 wherein said computing means includesadditional frequency multiplying means for producing an output pulsetrain having a frequency proportional to the product of the frequenciesof said revolution rate and the output of said additional frequencysquaring means, first and second frequency-to-voltage convertersrespectively connected to the outputs of said frequency multiplyingmeans and said additional frequency multiplying means, and a differenceamplifier connected to the outputs of said frequency-to-voltageconverter.

11. A combination as in claim 5 further comprising a fuel flow meter,and divider means having inputs connected to said fuel flow meter and tothe output of said frequency multiplying means.

12. A combination as in claim 11 wherein said divider comprises afeedback network including a frequency comparator, frequency multiplyingnetwork, and voltage controlled oscillator connected intermediate bysaid comparator and said frequency multiplying network.

13. In combination in torque metering apparatus, transducer means forgenerating an output digital signal having a frequency proportional tothe square root of torque, and digital wave frequency squaring meanscoupled to said transducer means for producing an output pulse trainhaving a frequency proportional to the square of said frequencygenerated by said transducer means, said digital wave frequency squaringmeans including rate multiplication means.

14. A combination as in claim 13 further comprising plural stageregister means, repetitive time interval signaling means, and meansincluding plural stage counter means responsive to signaling from saidtime interval signaling means for storing a measure of the digitalpulses from said wave frequency squaring means, occurring during eachtimed interval, in said register means.

1. In combination in apparatus for measuring physical parametersassociated with a stressed body having a vibrating wire transducermounted thereon for providing an output signal which varies in frequencywith the applied stress, means for providing an output pulse trainhaving a frequency proportional to the square of the transducerfrequency, said frequency square proportional means comprising a firstcounter having a plurality of stages, means connected to each of saidfirst counter stages for producing an output pulse responsive to apredetermined voltage transition for said counter, a plural stage secondcounter, means for supplying a measure of the transducer frequency toeach of said first and second counters, a plural stage data register,means for periodically gating the contents of said second counter intosaid data register, means for periodically resetting said second counterafter data is transferred from said second counter to said register, aplurality of coincidence logic gates each having inputs connected to adifferent one of said pulse generating means and to a different stage ofsaid register, said connections for the inputs to the coincidence gatesbeing of an inverse order of significance with respect to the stages ofsaid first counter and the stages of said register, and disjunctivelogic means for providing an output pulse responsive to an output signalfrom any of said coincidence gates, said disjunctive logic means therebyproviding a pulse rate of frequency proportional to the stress obtainingin the stressed body.
 2. A combination as in claim 1 further comprisingfrequency-to-voltage converting means connected to the output of saiddisjunctive logic means for producing an output analog signal.
 3. Acombination as in claim 1 wherein said counter stages each compriseactive, low impedance output driver means for the zero to one statetransition, and wherein said pulse producing means connected to each ofsaid first counter stages comprises a differentiator.
 4. A combinationas in claim 1 wherein the input of said second counter is connected tothe output of one of the stages of said first counter, such that thetransducer output information is averaged for an extended period oftime.
 5. In combination in means for measuring parameters associatedwith a rotating shaft, vibrating wire transducer means secured to saidshaft for generating an output signal characterized by a frequency whichvaries with the torsion present in the shaft, frequency squaring meansfor producing a pulse train having a frequency proportional to thesquare of said transducer output frequency, means for developing a pulsetrain proportional to the rate of rotation of the shaft, and frequencymultiplying means for producing an output pulse train having a frequencyproportional to the product of said revolution rate pulse trainfrequency and the frequency of the output pulses generated by saidfrequency squaring means.
 6. A combination as in claim 5, furthercomprising frequency-to-voltage converting means connected to the outputof said frequency multiplying means.
 7. A combination as in claim 5wherein said frequency multiplying means includes register means forstoring one input frequency variable in parallel binary form, andfurther comprising digital-to-analog converter means connected to saidregister means of said frequency multiplying circuit.
 8. A combinationas in claim 5 wherein at least one of said frequency squaring means andsaid frequency multiplying means comprises first and second counterseach having a plurality of stages, plural pulse generating Means eachconnected to a different stage of said first counter for generating anoutput pulse responsive to each zero to one level transition for theassociated stage of said first counter, a plural stage latch having aplurality of inputs connected to said second counter, timing means forperiodically transferring data from said second counter to said latchand for resetting said latch, plural coincidence logic gates, eachhaving first and second inputs connected to said pulse generating meansand to said latch stages in an inverse order of significance, anddisjunctive logic means including plural inputs connected to the outputsof each of said coincidence gates.
 9. A combination as in claim 5further comprising additional transducer means secured to the shaft andcircumferentially aligned with said transducer means for providing anoutput signal frequency which varies from a quiescent frequency in adirection opposite to said transducer means, additional frequencysquaring means for producing an output pulse train having a frequencyproportional to the square of the output frequency of said additionaltransducer means, and means for providing a horsepower signal comprisingmeans for computing the product of said shaft rate of revolution and thedifference in frequencies of the output pulse trains generated by saidfrequency squaring means and said additional frequency squaring means.10. A combination as in claim 9 wherein said computing means includesadditional frequency multiplying means for producing an output pulsetrain having a frequency proportional to the product of the frequenciesof said revolution rate and the output of said additional frequencysquaring means, first and second frequency-to-voltage convertersrespectively connected to the outputs of said frequency multiplyingmeans and said additional frequency multiplying means, and a differenceamplifier connected to the outputs of said frequency-to-voltageconverter.
 11. A combination as in claim 5 further comprising a fuelflow meter, and divider means having inputs connected to said fuel flowmeter and to the output of said frequency multiplying means.
 12. Acombination as in claim 11 wherein said divider comprises a feedbacknetwork including a frequency comparator, frequency multiplying network,and voltage controlled oscillator connected intermediate by saidcomparator and said frequency multiplying network.
 13. In combination intorque metering apparatus, transducer means for generating an outputdigital signal having a frequency proportional to the square root oftorque, and digital wave frequency squaring means coupled to saidtransducer means for producing an output pulse train having a frequencyproportional to the square of said frequency generated by saidtransducer means, said digital wave frequency squaring means includingrate multiplication means.
 14. A combination as in claim 13 furthercomprising plural stage register means, repetitive time intervalsignaling means, and means including plural stage counter meansresponsive to signaling from said time interval signaling means forstoring a measure of the digital pulses from said wave frequencysquaring means, occurring during each timed interval, in said registermeans.